I miss MPW – this was Apple’s Macintosh Programmer Workshop. The shell was a full text-editor window that you could type in, but if you hit Enter (instead of Return) at the end of a line, or you selected several lines and hit Enter, it would execute those as commands. Output went to the insertion point, or to the point right after the selection.
The plus side was that you had these worksheets that had all your previous commands and their output. You had a default worksheet, but you could open up any file and use it as a worksheet. There were multiple downsides as well, which is one of the reasons why MPW died (it wasn’t a real console or terminal, tools couldn’t run other tools, etc). But as a programmer-working-on-a-system, it was a great idea.
With more smarts in the editor, it could help you curate stuff, or have a much better search interface. Someone should write this for me. The world will love you.